diff --git a/src/df.c b/src/df.c

index e28a656..fe222d9 100644

--- a/src/df.c

+++ b/src/df.c

@@ -45,12 +45,12 @@

 /* Filled with device numbers of examined file systems to avoid

    duplicities in output.  */

-struct devlist

+static struct devlist

 {

   dev_t dev_num;

   struct mount_entry *me;

   struct devlist *next;

-};

+} *device_list;

 /* If true, show even file systems with zero size or

    uninteresting types.  */

@@ -609,13 +609,10 @@ excluded_fstype (const char *fstype)

    me_mountdir wins.  */

 static void

-filter_mount_list (void)

+filter_mount_list (bool devices_only)

 {

   struct mount_entry *me;

-  /* Store of already-processed device numbers.  */

-  struct devlist *devlist_head = NULL;

-

   /* Sort all 'wanted' entries into the list devlist_head.  */

   for (me = mount_list; me;)

     {

@@ -623,41 +620,66 @@ filter_mount_list (void)

       struct devlist *devlist;

       struct mount_entry *discard_me = NULL;

-      if (-1 == stat (me->me_mountdir, &buf))

+      /* Avoid stating remote file systems as that may hang.

+         On Linux we probably have me_dev populated from /proc/self/mountinfo,

+         however we still stat() in case another device was mounted later.  */

+      if ((me->me_remote && show_local_fs)

+          || -1 == stat (me->me_mountdir, &buf))

         {

-          /* Stat failed - add ME to be able to complain about it later.  */

+          /* If remote, and showing just local, add ME for filtering later.

+             If stat failed; add ME to be able to complain about it later.  */

           buf.st_dev = me->me_dev;

         }

       else

         {

-          /* If the device name is a real path name ...  */

-          if (strchr (me->me_devname, '/'))

-            {

-              /* ... try to find its device number in the devlist.  */

-              for (devlist = devlist_head; devlist; devlist = devlist->next)

-                if (devlist->dev_num == buf.st_dev)

-                  break;

+          /* If we've already seen this device...  */

+          for (devlist = device_list; devlist; devlist = devlist->next)

+            if (devlist->dev_num == buf.st_dev)

+              break;

-              if (devlist)

+          if (devlist)

+            {

+              if (! print_grand_total && me->me_remote && devlist->me->me_remote

+                  && ! STREQ (devlist->me->me_devname, me->me_devname))

                 {

+                  /* Don't discard remote entries with different locations,

+                     as these are more likely to be explicitly mounted.

+                     However avoid this when producing a total to give

+                     a more accurate value in that case.  */

+                }

+              else if ((strchr (me->me_devname, '/')

+                       /* let "real" devices with '/' in the name win.  */

+                        && ! strchr (devlist->me->me_devname, '/'))

+                       /* let a shorter mountdir win.  */

+                       || (strlen (devlist->me->me_mountdir)

+                           > strlen (me->me_mountdir))

+                       /* let an entry overmounted on a new device win...  */

+                       || (! STREQ (devlist->me->me_devname, me->me_devname)

+                           /* ... but only when matching an existing mnt point,

+                              to avoid problematic replacement when given

+                              inaccurate mount lists, seen with some chroot

+                              environments for example.  */

+                           && STREQ (me->me_mountdir,

+                                     devlist->me->me_mountdir)))

+                {

+                  /* Discard mount entry for existing device.  */

+                  discard_me = devlist->me;

+                  devlist->me = me;

+                }

+              else

+                {

+                  /* Discard mount entry currently being processed.  */

                   discard_me = me;

-

-                  /* Let the shorter mountdir win.  */

-                  if (! strchr (devlist->me->me_devname, '/')

-                      || (strlen (devlist->me->me_mountdir)

-                         > strlen (me->me_mountdir)))

-                    {

-                      discard_me = devlist->me;

-                      devlist->me = me;

-                    }

                 }

+

             }

         }

       if (discard_me)

         {

            me = me->me_next;

-           free_mount_entry (discard_me);

+           if (! devices_only)

+             free_mount_entry (discard_me);

         }

       else

         {

@@ -665,28 +687,49 @@ filter_mount_list (void)

           devlist = xmalloc (sizeof *devlist);

           devlist->me = me;

           devlist->dev_num = buf.st_dev;

-          devlist->next = devlist_head;

-          devlist_head = devlist;

+          devlist->next = device_list;

+          device_list = devlist;

           me = me->me_next;

         }

     }

   /* Finally rebuild the mount_list from the devlist.  */

-  mount_list = NULL;

-  while (devlist_head)

+  if (! devices_only) {

+    mount_list = NULL;

+    while (device_list)

+      {

+        /* Add the mount entry.  */

+        me = device_list->me;

+        me->me_next = mount_list;

+        mount_list = me;

+        /* Free devlist entry and advance.  */

+        struct devlist *devlist = device_list->next;

+        free (device_list);

+        device_list = devlist;

+      }

+  }

+}

+

+/* Search a mount entry list for device id DEV.

+   Return the corresponding mount entry if found or NULL if not.  */

+

+static struct mount_entry const * _GL_ATTRIBUTE_PURE

+me_for_dev (dev_t dev)

+{

+  struct devlist *dl = device_list;

+

+  while (dl)

     {

-      /* Add the mount entry.  */

-      me = devlist_head->me;

-      me->me_next = mount_list;

-      mount_list = me;

-      /* Free devlist entry and advance.  */

-      struct devlist *devlist = devlist_head->next;

-      free (devlist_head);

-      devlist_head = devlist;

+      if (dl->dev_num == dev)

+        return dl->me;

+      dl = dl->next;

     }

+

+  return NULL;

 }

+

 /* Return true if N is a known integer value.  On many file systems,

    UINTMAX_MAX represents an unknown value; on AIX, UINTMAX_MAX - 1

    represents unknown.  Use a rule that works on AIX file systems, and

@@ -856,6 +899,11 @@ get_dev (char const *disk, char const *mount_point, char const* file,

   if (!selected_fstype (fstype) || excluded_fstype (fstype))

     return;

+  /* Ignore relative MOUNT_POINTs, which are present for example

+     in /proc/mounts on Linux with network namespaces.  */

+  if (!force_fsu && mount_point && ! IS_ABSOLUTE_FILE_NAME (mount_point))

+    return;

+

   /* If MOUNT_POINT is NULL, then the file system is not mounted, and this

      program reports on the file system that the special file is on.

      It would be better to report on the unmounted file system,

@@ -868,9 +916,43 @@ get_dev (char const *disk, char const *mount_point, char const* file,

     fsu = *force_fsu;

   else if (get_fs_usage (stat_file, disk, &fsu))

     {

-      error (0, errno, "%s", quote (stat_file));

-      exit_status = EXIT_FAILURE;

-      return;

+      /* If we can't access a system provided entry due

+         to it not being present (now), or due to permissions,

+         just output placeholder values rather than failing.  */

+      if (process_all && (errno == EACCES || errno == ENOENT))

+        {

+          if (! show_all_fs)

+            return;

+

+          fstype = "-";

+          fsu.fsu_blocksize = fsu.fsu_blocks = fsu.fsu_bfree =

+          fsu.fsu_bavail = fsu.fsu_files = fsu.fsu_ffree = UINTMAX_MAX;

+        }

+      else

+        {

+          error (0, errno, "%s", quote (stat_file));

+          exit_status = EXIT_FAILURE;

+          return;

+        }

+    }

+  else if (process_all && show_all_fs)

+    {

+      /* Ensure we don't output incorrect stats for over-mounted directories.

+         Discard stats when the device name doesn't match.  Though don't

+         discard when used and current mount entries are both remote due

+         to the possibility of aliased host names or exports.  */

+      struct stat sb;

+      if (stat (stat_file, &sb) == 0)

+        {

+          struct mount_entry const * dev_me = me_for_dev (sb.st_dev);

+          if (dev_me && ! STREQ (dev_me->me_devname, disk)

+              && (! dev_me->me_remote || ! me_remote))

+            {

+              fstype = "-";

+              fsu.fsu_blocksize = fsu.fsu_blocks = fsu.fsu_bfree =

+              fsu.fsu_bavail = fsu.fsu_files = fsu.fsu_ffree = UINTMAX_MAX;

+            }

+        }

     }

   if (fsu.fsu_blocks == 0 && !show_all_fs && !show_listed_fs)

@@ -1275,8 +1357,7 @@ get_all_entries (void)

 {

   struct mount_entry *me;

-  if (!show_all_fs)

-    filter_mount_list ();

+  filter_mount_list (show_all_fs);

   for (me = mount_list; me; me = me->me_next)

     get_dev (me->me_devname, me->me_mountdir, NULL, NULL, me->me_type,

@@ -1325,7 +1406,7 @@ or all file systems by default.\n\

       emit_mandatory_arg_note ();

       fputs (_("\

-  -a, --all             include dummy file systems\n\

+  -a, --all             include pseudo, duplicate, inaccessible file systems\n\

   -B, --block-size=SIZE  scale sizes by SIZE before printing them; e.g.,\n\

                            '-BM' prints sizes in units of 1,048,576 bytes;\n\

                            see SIZE format below\n\

diff --git a/doc/coreutils.texi b/doc/coreutils.texi

index 942d9a1..1df1eac 100644

--- a/doc/coreutils.texi

+++ b/doc/coreutils.texi

@@ -11123,11 +11123,15 @@ The program accepts the following options.  Also see @ref{Common options}.

 @itemx --all

 @opindex -a

 @opindex --all

-@cindex automounter file systems

 @cindex ignore file systems

-Include in the listing dummy file systems, which

-are omitted by default.  Such file systems are typically special-purpose

-pseudo-file-systems, such as automounter entries.

+Include in the listing dummy, duplicate, or inaccessible file systems, which

+are omitted by default. Dummy file systems are typically special purpose

+pseudo file systems such as @samp{/proc}, with no associated storage.

+Duplicate file systems are local or remote file systems that are mounted

+at separate locations in the local file hierarchy, or bind mounted locations.

+Inaccessible file systems are those which are mounted but subsequently

+over-mounted by another file system at that point, or otherwise inaccessible

+due to permissions of the mount point etc.

 @item -B @var{size}

 @itemx --block-size=@var{size}

diff --git a/tests/df/skip-duplicates.sh b/tests/df/skip-duplicates.sh

index 1e94dc0..4069604 100755

--- a/tests/df/skip-duplicates.sh

+++ b/tests/df/skip-duplicates.sh

@@ -2,7 +2,7 @@

 # Test df's behavior when the mount list contains duplicate entries.

 # This test is skipped on systems that lack LD_PRELOAD support; that's fine.

-# Copyright (C) 2012-2013 Free Software Foundation, Inc.

+# Copyright (C) 2012-2015 Free Software Foundation, Inc.

 # This program is free software: you can redistribute it and/or modify

 # it under the terms of the GNU General Public License as published by

@@ -21,19 +21,73 @@

 print_ver_ df

 require_gcc_shared_

-df || skip_ "df fails"

+# We use --local here so as to not activate

+# potentially very many remote mounts.

+df --local || skip_ 'df fails'

-# Simulate an mtab file with two entries of the same device number.

-# Also add entries with unstatable mount dirs to ensure that's handled.

-cat > k.c <<'EOF' || framework_failure_

+export CU_NONROOT_FS=$(df --local --output=target 2>&1 | grep /. | head -n1)

+export CU_REMOTE_FS=$(df --local --output=target 2>&1 | grep /. |

+                      tail -n+2 | head -n1)

+

+unique_entries=1

+test -z "$CU_NONROOT_FS" || unique_entries=$(expr $unique_entries + 1)

+test -z "$CU_REMOTE_FS" || unique_entries=$(expr $unique_entries + 2)

+

+grep '^#define HAVE_MNTENT_H 1' $CONFIG_HEADER > /dev/null \

+      || skip_ "no mntent.h available to confirm the interface"

+

+grep '^#define HAVE_GETMNTENT 1' $CONFIG_HEADER > /dev/null \

+      || skip_ "getmntent is not used on this system"

+

+# Simulate an mtab file to test various cases.

+cat > k.c <

+#define _GNU_SOURCE

 #include <stdio.h>

 #include <stdlib.h>

+#include <errno.h>

 #include <mntent.h>

+#include <string.h>

+#include <dlfcn.h>

+

+#define STREQ(a, b) (strcmp (a, b) == 0)

+

+FILE* fopen(const char *path, const char *mode)

+{

+  static FILE* (*fopen_func)(char const *, char const *);

+

+  /* get reference to original (libc provided) fopen */

+  if (!fopen_func)

+    {

+      fopen_func = (FILE*(*)(char const *, char const *))

+                   dlsym(RTLD_NEXT, "fopen");

+      if (!fopen_func)

+        {

+          fprintf (stderr, "Failed to find fopen()\n");

+          errno = ESRCH;

+          return NULL;

+        }

+    }

+

+  /* Returning ENOENT here will get read_file_system_list()

+     to fall back to using getmntent() below.  */

+  if (STREQ (path, "/proc/self/mountinfo"))

+    {

+      errno = ENOENT;

+      return NULL;

+    }

+  else

+    return fopen_func(path, mode);

+}

+

+#define STREQ(a, b) (strcmp (a, b) == 0)

 struct mntent *getmntent (FILE *fp)

 {

+  static char *nonroot_fs;

+  static char *remote_fs;

+  static int done;

+

   /* Prove that LD_PRELOAD works. */

-  static int done = 0;

   if (!done)

     {

       fclose (fopen ("x", "w"));

@@ -41,50 +95,92 @@ struct mntent *getmntent (FILE *fp)

     }

   static struct mntent mntents[] = {

-    {.mnt_fsname="/short",  .mnt_dir="/invalid/mount/dir"},

-    {.mnt_fsname="fsname",  .mnt_dir="/",},

-    {.mnt_fsname="/fsname", .mnt_dir="/root"},

-    {.mnt_fsname="/fsname", .mnt_dir="/"},

+    {.mnt_fsname="/short",  .mnt_dir="/invalid/mount/dir",       .mnt_opts=""},

+    {.mnt_fsname="fsname",  .mnt_dir="/",                        .mnt_opts=""},

+    {.mnt_fsname="/fsname", .mnt_dir="/.",                       .mnt_opts=""},

+    {.mnt_fsname="/fsname", .mnt_dir="/",                        .mnt_opts=""},

+    {.mnt_fsname="virtfs",  .mnt_dir="/NONROOT", .mnt_type="t1", .mnt_opts=""},

+    {.mnt_fsname="virtfs2", .mnt_dir="/NONROOT", .mnt_type="t2", .mnt_opts=""},

+    {.mnt_fsname="netns",   .mnt_dir="net:[1234567]",            .mnt_opts=""},

+    {.mnt_fsname="rem:ote1",.mnt_dir="/REMOTE",                  .mnt_opts=""},

+    {.mnt_fsname="rem:ote1",.mnt_dir="/REMOTE",                  .mnt_opts=""},

+    {.mnt_fsname="rem:ote2",.mnt_dir="/REMOTE",                  .mnt_opts=""},

   };

-  if (!getenv ("CU_TEST_DUPE_INVALID") && done == 1)

+  if (done == 1)

+    {

+      nonroot_fs = getenv ("CU_NONROOT_FS");

+      if (!nonroot_fs || !*nonroot_fs)

+        nonroot_fs = "/"; /* merge into / entries.  */

+

+      remote_fs = getenv ("CU_REMOTE_FS");

+    }

+

+  if (done == 1 && !getenv ("CU_TEST_DUPE_INVALID"))

     done++;  /* skip the first entry.  */

-  while (done++ <= 4)

+  while (done++ <= 10)

     {

-      mntents[done-2].mnt_type = "-";

+      if (!mntents[done-2].mnt_type)

+        mntents[done-2].mnt_type = "-";

+      if (!mntents[done-2].mnt_opts)

+        mntents[done-2].mnt_opts = "-";

+      if (STREQ (mntents[done-2].mnt_dir, "/NONROOT"))

+        mntents[done-2].mnt_dir = nonroot_fs;

+      if (STREQ (mntents[done-2].mnt_dir, "/REMOTE"))

+        {

+          if (!remote_fs || !*remote_fs)

+            continue;

+          else

+            mntents[done-2].mnt_dir = remote_fs;

+        }

       return &mntents[done-2];

     }

+

   return NULL;

 }

 EOF

 # Then compile/link it:

-gcc --std=gnu99 -shared -fPIC -ldl -O2 k.c -o k.so \

+gcc_shared_ k.c k.so \

   || framework_failure_ 'failed to build shared library'

 # Test if LD_PRELOAD works:

-LD_PRELOAD=./k.so df

+LD_PRELOAD=$LD_PRELOAD:./k.so df

 test -f x || skip_ "internal test failure: maybe LD_PRELOAD doesn't work?"

 # The fake mtab file should only contain entries

 # having the same device number; thus the output should

-# consist of a header and one entry.

-LD_PRELOAD=./k.so df >out || fail=1

-test $(wc -l 

+# consist of a header and unique entries.

+LD_PRELOAD=$LD_PRELOAD:./k.so df -T >out || fail=1

+test $(wc -l 

-# Ensure we fail when unable to stat invalid entries

-LD_PRELOAD=./k.so CU_TEST_DUPE_INVALID=1 df >out && fail=1

-test $(wc -l 

+# With --total we should suppress the duplicate but separate remote file system

+LD_PRELOAD=$LD_PRELOAD:./k.so df --total >out || fail=1

+test "$CU_REMOTE_FS" && elide_remote=1 || elide_remote=0

+test $(wc -l 

+  { fail=1; cat out; }

+

+# Ensure we don't fail when unable to stat (currently) unavailable entries

+LD_PRELOAD=$LD_PRELOAD:./k.so CU_TEST_DUPE_INVALID=1 df -T >out || fail=1

+test $(wc -l 

 # df should also prefer "/fsname" over "fsname"

-test $(grep -c '/fsname' 

-# ... and "/fsname" with '/' as Mounted on over '/root'

-test $(grep -c '/root' 

+if test "$unique_entries" = 2; then

+  test $(grep -c '/fsname' 

+  # ... and "/fsname" with '/' as Mounted on over '/.'

+  test $(grep -cF '/.' 

+fi

+

+# df should use the last seen devname (mnt_fsname) and devtype (mnt_type)

+test $(grep -c 'virtfs2.*t2' 

 # Ensure that filtering duplicates does not affect -a processing.

-LD_PRELOAD=./k.so df -a >out || fail=1

-test $(wc -l 

+LD_PRELOAD=$LD_PRELOAD:./k.so df -a >out || fail=1

+total_fs=6; test "$CU_REMOTE_FS" && total_fs=$(expr $total_fs + 3)

+test $(wc -l 

+# Ensure placeholder "-" values used for the eclipsed "virtfs"

+test $(grep -c 'virtfs *-' 

 # Ensure that filtering duplicates does not affect

 # argument processing (now without the fake getmntent()).

diff --git a/init.cfg b/init.cfg

index 360d4da..16f9813 100644

--- a/init.cfg

+++ b/init.cfg

@@ -472,6 +472,18 @@ require_sparse_support_()

   fi

 }

+# Compile a shared lib using the GCC options for doing so.

+# Pass input and output file as parameters respectively.

+# Any other optional parmeters are passed to $CC.

+gcc_shared_()

+{

+  local in=$1

+  local out=$2

+  shift 2 || return 1

+

+  $CC -Wall -shared --std=gnu99 -fPIC -O2 $* "$in" -o "$out" -ldl

+}

+

 # There are a myriad of ways to build shared libs,

 # so we only consider running tests requiring shared libs,

 # on platforms that support building them as follows.